There are many mechanical devices in which travel must be limited by mechanical stops. Accordingly, there are many mechanical stops for varying applications. These mechanical stops range from very simple to very complex. As with most mechanical devices the simpler the structure the more reliable the device. Therefore, the simpler the mechanical stop the more reliable the stop will be. A simple door check is disclosed in U.S. Pat. No. 533,694 issued to Wilson on Feb. 5, 1895. In this patent a pivoting angular or L-shaped member is disclosed in which a door is held open by one of its legs.
More complex stops were necessitated when the stopping requirements became more complex. This is especially true in the stops used to limit rotation. Stops exist to limit rotation after one, two, or multiple revolutions. One such stop limiting rotation after two revolutions is disclosed in U.S. Pat. No. 2,780,941 entitled "Multiple Revolution Limit Stop Device" issued to Kollmorgan on Feb. 12, 1957. This patent discloses concentric sleeves having a space containing a ball therein. The ball being recessed in a peripheral groove is permitted to rotate within the space between the concentric sleeves. A pin or lug is affixed to each sleeve which extends into the space and interacts with the ball to limit relative rotation of the sleeves to slightly less than two revolutions.
Another two revolution mechanical stop is disclosed in U.S. Pat. No. 3,012,447 entitled "Two-Revolution Mechanical Stop" issued to Wallace on Dec. 12, 1961. This patent discloses a rotating disk containing a tooth on the periphery. The disk when rotated contacts a two tooth rotatably mounted pivot stop. As the disk rotates its tooth will engage the pivot stop and cause the pivot stop to rotate in the direction of the movement of the disk bringing the second tooth into a vertical position. As the disk makes a second revolution and strikes the second upwardly extending tooth the disk will be prevented from continuing its rotation. In this way the disk is limited to two revolutions. This device can not be adjusted to provide varying rotation between one and two revolutions.
Other devices have been described providing a mechanical stop after multiple turns. The mechanical stops which provide for more than two revolutions are generally complex. For example, U.S. Pat. No. 1,899,250 entitled "Full Stroke Mechanism" issued to Wheelbarger et al on Feb. 28, 1933 and U.S. Pat. No. 3,147,629 entitled "Multiturn Stop" issued to Michalec on Sept. 8, 1964.
While all of these stops have contributed to advancements in the art none can adequately address the situation where more than one but less than two revolutions are needed. It is therefore necessary to turn away from the teachings of the prior art and establish a new and innovative approach to the construction of a mechanical stop.